Depth charge firing control mechanism



June 3, 1958 B ET AL 2,837,026

DEPTH CHARGE FIRING CONTROL MECHANISM I Filed March 18, 1953 INVENTORS50L 0M0 BURG m C a m M m B Tut 2,833,925 Patented June 3, 1958 5 Claims.((15. 102-16) The invention described herein may be manufactured andused by or for the Government of the United States of America forgovernmental purposes without the payment of any royalties thereon ortherefor.

This invention relates to improvements in naval ordnance, and itsunderlying purpose is to improve the depth-set valve mechanism ofunderwater explosivecharges.

The improvement has special reference to United States Patent 2,438,ll7of March 23, 1948, Walter B. Ellwood for Valve for Depth Charge FiringMechanisms, which in practice was found to develop several faults. Byreference to the patent it is noted that a ball valve is seated in theconic csncavity of a ball-centering flange. This was found to have atendency to leak water because of its being loose in the cavity couldnot be prevented from damaging one side of the seat during testing.

Further, a large coil spring immediately behind the ball-centeringflange was found responsible for some erratic opening pressures becauseof failure to maintain a uniform seating on a conical rest provided forit. Because of the inherent resilience of the spring, the end loop wouldopen slightly, allowing the spring to slip down the cone and sometimescock oil to one side. Still further, some lost motion was found todevelop in the thread course of the spring seat member, functionally thedepth adjusting screw, introducing some variations when adjusting thatscrew that were reflected in diflerences of force of the spring againstthe ballcentering flange.

Another fault of the Ellwood mechanism was an objectionable chatteringof the valve assembly upon water inflow, due to the restriction.

Therefore, it is one of the objects of the invention to provide anunderwater missile with means therein to increase the accuracy of thedepth setting by (a) eliminating variations in the setting resultingfrom backlash in the threads of the adjusting screw and (b) arrangingthe dial and d-etent mechanism in such a manner as to utilize themaximum diameter of the weapon as an index to the depth setting.

Another object of the invention is to improve the nose piece of theWeapon by (a) affixing the ball valve to the adjacent ball-centeringflange or piston, thus to avoid damaging the valve seat during testingas by the rolling of the ball valve if it were loose, (1)) providing anadequate seating for the large coil spring so that its opening pressurescan be relied on and c) supplementing the spring seat member with a leafspring to prevent rotation of the spring seat member relative to thevalve body during the making of a setting by means of the adjustingcylinder.

Another object of the invention is to increase the length of the passagearound the foregoing circular flange thereby, rather paradoxically,increasing the marine warfare.

facility for water inflow into the chambers of the mechanism and therebyinsuring an immediate and full opening of the ball valve member, thus toavoid any possibility of. initiating a chatter.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. l is a central, longitudinal section of the valve assembly indetail mounted in a portion of the body section, shown in phantom, ofthe improved depth charge;

Fig. 2 is a sectional view taken on the line 22 of Fig. 1.

In the drawings the depth charge is commonly designated 11. Its intendeduse is in practice anti-sub- This, however, is no limitation upon theuse of the missile since the identical structure and principle ofoperation will obtain when produced for actual warfare. It may behand-launched or started on its air trajectory by a mechanical orexplosive project of a chosen type. In the first instance the missile issimply dropped overboard or dropped from an aircraft. The missile maytake shapes other than that shown such as, for example, in the form of apotato-masher and grenade.

In Fig. l the depth charge 11 is shown to comprise a spherical nosepiece 29, and a body section 31 which may house an arming mechanism. Thenose piece is built up on an annular base 33. This base is afiixed bymeans of a mutual thread course 36 to the socket 34 of a bulkhead 35 atthe forward end of the section 31. Most of the socket is filled by thebase 33 and attachments, but some space is left to define the chamber37.

The base 33 is provided with a central bore 38 in which a hollowcylinder 39 is turnably mounted. Turning of said cylinder occurs atdepth setting. A water-tight joint is formed by sealing ring 40 and itscompression nut 4-1. The head 42 at the front end of the cylinder 39 hasa central passage 43, the inner circular edge of which provides the seatfor the ball valve 44-. Seawater is admitted to the inside of thecylinder 39 according to the amount of unseating of the ball valve.

A second ring 47, part of a sphere, completes the symmetrical shape ofthe nose piece. It is seated on the cylinder 33 and locked thereto by ascrew 48 so that the two turn as one. A snap catch 49 operativelycarried by the ring 47 engages any one of several recesses 54 in thefront face of the base 33 as turning occurs. The exposed perimeter ofthe base 33 is marked in practice with depth setting indicia from 50 to1000 feet (not shown). These indicia are distributed to match thepositions of the recesses, and by locating the recesses as near aspossible to the perimeter of the base it becomes possible to obtain adepth setting more easily and accurately than with the crampedarrangement in the Ellwood patent. It is the greater peripheral spacingof the recesses that makes the distinction from the Ellwood structure.Any setting is held by the snapping of the detent 49 into the matchingrecesses.

Bolts 51 secure an inwardly flanged ring 52 against the back of the base33. This ring has a working fit against the flanged terminal 53 of theturnable cylinder 39, rotatably mounting the cylinder on the base 33 andpreventin g longitudinal movement of it. The outer ends of a wide leafspring 54 are clamped under the heads of the bolts 51. This spring isthus affixed to the base 33 and remains rotationally but not axiallyimmovable with it. The spring 54 is anchored at its middle to the innerend of an adjustable screw plug or spring seat member 55 by means of ahollow machine screw 56, thereby holding the spring seat memberrotationally immovable with the base 33. Corrugations are provided inthe leaf spring to permit the same to elongate axially as plug 55 ismoved toward the ball and to cause the spring to exert tension on thescrew plug 55 in the same direction as the force due to a coil spring 57abutting a flat seat 58 adjacent tothe opposite end of the plug.

The leaf spring 54 serves to maintain the contact of the threads in thethread course 59 between the plug 55 and the bore 60 of the cylinder 39on the same faces at all times. The coil spring 57 is virtually dormantas far as ex'terting pressure against the mating faces of the threads ofthe thread course between 39 and 55 and seat 58 is concerned when thevalve is set in its shallowest depth (50 ft.) position. The front end ofthe coil spring has a flat seat against the back of a freely slidablepiston 61, the length of which piston is approximately equal to one-halfits diameter. The side wall is circularly grooved, and its front facehas a recess at 62 in which the ball valve 44 is aflixed by a volume ofa suitable adherent 63, usually solder. The ball is thus held in itscorrect position and its correct seating on the inner circular edge ofthe passage 43 is assured.

A rod with portions having diameters 64 and 64a and 64!) extends backfrom the rear of the piston 61. The portion having the diameter 64serves as a stop by abutting against plug 55 to prevent spring 57 frombeing compressed to a solid height. The second portion having thediameter 64a has slidable mounting in the bore 65 of the plug 55, theback end of which bore has a thread course into which the machine screw56 is driven. The third portion having the diameter 64!) is slidablymounted in the hollow of the machine screw. The nut 66 screwed on theexposed rear end of the reduction 6412, which is conveniently called astem, is adjustable against the head of the screw 56 to determine themaximum length to which the spring 57 may extend. When the valve is seton the 50-foot setting the spring 57 does not exert 1 any force on themating faces of the thread course between est setting, the depth offiring may be determined only by the characteristics of means such as afiring pin mechanlsm.

The spring 57 has predetermined compression characteristics with whichthe depth setting indicia on the perimeter of the base 33 are directlyrelated. This spring is varied in its pressure against the piston 61 andin consequence in the pressure which it exerts to seat the ball valve44, by rotation of the ring 47. In other words, if the depth setting isto be for the 300-foot mark, the turning of the ring 47 will rotatecylinder 39 and result in plug 55 being moved axially an amount suchthat the spring exerts a force on the ball valve equal to the forceexerted by the external hydrostatic pressure of water at a depth 300feet below the surface.

Slight unseating of the ball valve admits water to the face of piston 61and immediately sets up a pressure over the entire area of the piston,displacing it backward and thus fully opening the valve. Merelyadmitting water does not accomplish any purpose if the flow past thepiston is not properly restricted to create the foregoing pressure onthe face'of the piston.

To the foregoing end it is noted that there is but a moderate clearanceand a fairly long skirt between the quickest possible filling of chamber37. The second purpose is to make the valve so that it will not close bybackpressure before actuation of a firing release mechanism, forexample. In other words, the build-up of pressure in chamber 37 mustoperate means such as a firing pin at the established setting before theback-pressure reaches the level at which it would counter-move thepiston and again close valve 44. If the latter happened during thesinking of the depth charge, the latter would have to go down muchfarther than intended to arrive at a pressure level at which the valvewould open again.

Unseating of the'valve 44 admits water to the chamber 37 through holes67 in the screw plug 55. This chamber adjoins the bulkhead fronting afiring pin release mechanism, not shown.

Obviously modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. An item of ordnance, the subcombination thereof comprising a ballvalve and a hollow cylinder having a central passage defining a seat forthe ball valve, a piston freely slidable in the hollow cylinder andhaving a recess for the ball valve, means adhering the ball valve in therecess, preventing its rolling sidewise in the recess and avoidingresulting damage to the seat on a sliding of the piston during a testoperation, a ported plug disposed within said cylinder and movablethereby, means on, said cylinder in engagement with complementary meanson said plug for moving said plug as the cylinder is rotated, means inclamping engagement with said plug for causing the plug to move axiallyin response to rotation of the I cylinder, means carried by saidcylinder for imparting rotary movement thereto, spring means inengagement.

with said plug and piston and controlled by said plug for maintainingthe ball valve in engagement with said seat, and means including aflange on said cylinder for preventing axial movement of the cylinder asthe cylinder is rotated.

2. An item of ordnance, the subcombination thereof comprising a ballvalve and a hollow cylinder having a central passage at one end defininga seat for the ball valve and having a thread course at the other end,abase for rotatably supporting said cylinder, flange means on saidcylinder in engagement with complementary means on said base by whichthe cylinder is swivelled on the base to turn but not move axially, aported plug screwed into the thread course and movable axially thereinas the cylinder is rotated, a movable piston in the hollow cylinder, astem on said piston disposed within said plug and slidably guided by theplug, a coil spring abutting the piston and plug and controlled by saidplug as the plug is moved axially for maintaining the ball valveseated,'means carried by said cylinder for rotating the cylinder andaxially shifting the plug at the thread course thereby to adjust thecompression of the coil spring, said last-named means being selectivelysettableto different settings relative to said base, means carried bysaid base in sealing engagement with the cylinder for providing awatertight connection therebetween, and a leaf spring affixed to thescrew plug and to the base to prevent turning of the plug without lostmotion.

3. The structure of claim 2 wherein the leaf spring is corrugatedcrosswise of its length to exert a tension on against axial movement, aported plug screwed into the thread course and having a bore, said plugbeing movable axially as said cylinder is rotated, means carried by saidcylinder for rotating said cylinder, said last-named means beingselectively settable to difierent settings relative to said base, apiston in the cylinder having a recess containing the ball valve andhaving a rod slidablc in the bore, a coil spring abutting the piston andplug and controlled by said plug for urging the ball valve intoengagement with its seat, a stern integral with the rod and ex tendingout of the bore, and a nut screwed onto the extension of the stem toexert pressure against the plug thus to preset the coil spring and holdthe valve open so that it is inseparable at the shallowest setting.

References Cited in the file of this patent UNITED STATES PATENTSHouston Jun 19, 1928 Thomson Oct. 2, 1934 Penrod June 18, 1935 EllwoodMar. 23, 1948 Chase Mar. 22, 1949 Moore Apr. 25, 1950 Bowersett June 24,1952 Cook Feb. 2, 1954 FOREIGN PATENTS France Mar. 15, 1912 GreatBritain Aug. 12, 1938

